We will quantitate the amount and types of releasable epoxide hydratase obtained from hyperplastic nodule and hepatoma microsomes during in vitro incubation. These species are also found in pre- and neoplastic cytosolic fractions, but not in normal liver cytosol. We will determine the immunological similarity or difference of a new polypeptide found in hepatoma microsomal incubation supernate and cytosol fractions, but not in normal, by immuno-affinity column techniques. We will purify this new polypeptide to certify its identification. We will assay hepatomas and any premalignant nodules, for releasable epoxide hydratase (PN Antigen Effect) from mouse strains that develop "spontaneous " hepatomas. One of these strains have an associated virus suspected of being involved in the carcinogenic process.